I've got one that has stumped FOT, and it's a two week wait for HWH to call me back. Maybe the braintrust can solve this
The air suspension works great in travel.
When I reach a campsite, autolevel (two clicks, top left) works fine... HWH lowers different sides until everything reaches level. Then we shut down engine, of course.
After a few days, invariably, the rear has leaked down. (Probably that six pack needs to be rebuilt, but who knows?)
But, at no point does HWH do what I expect it's supposed to: wake up every 30 minutes, see that we're not level, attempt to lower the high side, then realize we are on the stops and attempt to raise the low side, which should of course command the aux compressor to supply fresh air.
If I wake up the HWH by hand, it shows a yellow dot, which means it knows the side is low. And if I use any of the raise or lower buttons, they work fine -- including to turn on the aux compressor and raise.
If I push Auto twice to get another round of auto-level, the HWH goes through the attempt-to-lower again, like it should, but then it never issues the compressor-on command.
This feels like a logic issue more than a mechanical one, but I'm not sure. If you've got any ideas, I'm game to test them out. We probably won't get a chance to have a pro work on this before we head out for our long summer trip, but that's in part because it's not enough of a headache to worry about (I'll just manually re-level when we're stationary for a few days or longer). But I'd still like to figure it out, dang it!
I have the exact issue except mine doesn't leak down. When I talked to HWH tech the gentleman worked me through some tests and his conclusion is the the pressure switch is bad behind the compressor. I have jumped the solenoid and the compressor does work. Because of no leak down it is on the back burner as it is difficult to access.
Are you sure the aux compressor is functioning and has power?
That's quite interesting. Does your aux compressor run if you press Raise (manually)?
Yep, I can press any Raise button and it all works fine.
The only thing I've noticed is that my dash gauges never show any pressure in either tank, even if I power up the dash. Which seems unusual to me, versus what I've seen in previous coaches, but I feel like that's probably not relevant. (?)
On my old 1997U295 the compressor was very small and did a lousy job of trying to auto level. I got where I never auto leveled.
Does the compressor only run when you are pushing the raise button?
As said previously the pumps pressure switch might not be keeping the tank full of air. When pushing the button Hwh is telling compressor to run while you have raise button pushed. This is different circuit then pressure switch.
The HWH compressor should not be putting any air into the vehicle air tanks.
Never tried to level with the engine off. Will check that out.
When I was at Scotts place in January I leveled my coach and it was the first time that I've ever heard
my compressor come on. It turns out it is now leaking down in the leveling position. At Q the compressor
was bothering my son so I leveled the coach and put the coach back in travel mode by turning on the
ignition and releasing the parking brake for a few seconds and then set the parking brake an turned off
the ignition. The coach stayed level as there are no leaks in travel mode. The coach levels with engine off.
Also I would check your fuses in the control box. Maybe one is blown.
That was checked when the tech walked me through all the possibilities of my problem. He took about 15 minutes to have me check with a voltmeter different parts of the control box and it checked out as good to go.
Looks like we've got 2 different troubleshooting threads in this one: OP nebster's and craneman's - do I need to split them? I don't want the answers directed towards one to get confused with the other.
Just take mine out as I know my problem.
It seems like mine needs about 3 minutes to raise the front axle and maybe 10 to raise the back all the way. Pretty slow, but it gets there. It should never have to do that in day-to-day auto-level operation, though. Much smaller deltas should set it to re-leveling, I would hope.
That's true. There are actually five raise buttons, and it runs if I push any of them.
Others in this thread have said that the "tank" won't fill with air. (It's unclear which tank we're all talking about, and I admit I don't know how many there are or what they are named, either.) FOT tech today said I should be able to see pressure rise on one of the dash gauges when the aux compressor works, but that isn't what I observe.
It makes sense to me that, when I push Raise, the HWH controller energizes the compressor (
if there's not enough air available). What's less clear to me is why that's different than when HWH controller (should) decide to do the same thing on its own, during an auto-level re-level check.
That's interesting. Based on my limited understanding, that makes me think that travel mode keeps some of the air solenoids out of the loop, so to speak, and maybe you have one of those that leaks. But I'm not sure?
Anyway, it's worth a try as a way to get around the leakdown issue. But, on the other hand, the HWH should be able to deal with this using the compressor. I measured the leakdown at 1/4" on the rear bags per 6 hours today, so I would expect a relevel at most two times a day. If it worked.
Yes, good idea. I have found it, but it is hard to access in my FT. I will get into it this week, though.
Thanks!
Okay, the plot thickens: today, after concluding my leakdown rate experiment, I had a coach with ~11 inches of front air bags and ~6 inches of rear air bags, and on a slight slope.
So, I woke up the apparently-hiberating-for-spring HWH controller and pushed Auto twice to kick off a brand new autolevel. And, it lowered the front all the way, as expected, and still sensed a slightly low rear due to the slope of my driveway. But then I went outside... and heard the aux compressor on!
(I normally auto-level right after arriving, with full air in the tanks and the bags at ride height. So, presumably, there's no need for the aux compressor to do anything, since there's ample air everywhere to use.)
This gives one more hint: the HWH computer is capable of commanding the aux compressor on, without me pushing any manual Raise buttons.
So now I am thinking the HWH just doesn't know how to "wake up and re-level" anymore, somehow. And I bet that points to either a configuration issue, or a keypad or controller repair/replace.
The HWH has 2 sources of power. One from the chassis batteries and one from the house batteries. Remove the lid of the control box and look at the diagram on the inside of the lid and then you can see what wires receive power from where and then check that everything is getting power as it should. Again I will say that the aux compressor should not be putting air into your brake tanks.
This is an important point, and it's unfortunate that a current FOT tech claimed it should:
Perhaps on the new model coaches it does, but definitely not on a 1997.
2002 or 2003+ were equipped with a solenoid and a line that allows the aux compressor to add air to the brake tanks (switch marked "Air Tank" by the driver's elbow). That was added as a courtesy feature in that year (so you could air up for departure without running the coach engine and disturbing neighbors). Prior year coaches don't have that capability. It's also not a switch that should be employed often. And if the dash gauges go up when the aux compressor is on but that switch is off, that solenoid is leaking through and needs to be replaced/new plunger installed.
Ah, that makes a lot of sense. I was wondering how FOT could be wrong on such a basic thing, but if it changed over time, they might have gotten it oversimplified in their memory.
This is showing tank pressure has leaked down to zero? I hate ever hearing the aux compressor run so I always park and make sure system is OFF then IGN off. Mine doesn't leak down. Yes the dash indication will drop eventually but the level system will stay for weeks happily in the off position. In travel mode the travel solenoids are open and being managed by the ride height valves with an active air source from the engine. The other two solenoids are for commanded raise and commanded drop. I always prefer to when leveling manually drop coach and either auto level or adjust manually then shut off HWH followed by Ignition off. Often it is level after being dropped and that is how I leave it. It also is more stable if the rear tires are fully on the stops. This isn't how it was intended to be used but has worked well for me. Lower is better for access. My coach has a slide so this opens up an entirely different can of worms. The slide commands the compressor on as does the leveling regardless of the pressure, but usually you don't hear do to all the extra background noise for me with engine idling.
My 91 has the 120v compressor that ties into the main air system, so that one does fill all the tanks. Sounds like many variations across the years.
Does the Auto light flicker when it is in sleep mode? It should look like it's flashing pretty fast to indicate sleep after auto leveling.
Good question. It really doesn't seem to blink at all.
I had one HWH that only blinked very briefly every few minutes, so at first I thought I was just not waiting around and missing it. But maybe it is just somehow "off" all of the time.
Finally got around to checking that out. Yes the compressor does run when I push the buttons manually with the tanks down to 60 psi. But do not notice any movement on the air bags while doing so.
That little compressor doesn't put out much volume, so will take some time to see it raise the coach.